12 R. S. Tarr — The Permian of Texas. 



derived from points as far distant as the Indian Territory, 

 seem hardly capable of origin except in an inland sea with a 

 tolerably arid climate, or else by glaciation. 



The Permian was undoubtedly deposited in an inland sea in 

 which salt and gypsum were also deposited. The small break, 

 if any exists, between the Permian and Carboniferous, shows 

 that in point of time these two formations were immediately 

 associated, the one succeeding the other. This gradation is 

 also proved by the fossils. One of the distinctive Permian 

 types, Pleurophorus, occurs in the Coleman beds, while the 

 same species of Bellerophon, Myalina and others, are common 

 to the two series of beds. The Permian conditions are, there- 

 fore, foreshadowed in the Carboniferous, and probably, also, 

 the conditions which culminated in Permian times in the 

 completely enclosed dead sea were in Coleman times indicated 

 by the gathering in of shore lines and the partial enclosure of 

 a Mediterranean sea. The change of fauna from Carboniferous 

 to Permian, and also the close resemblance of the two in many 

 respects, as well as their wide divergence in others, may be 

 thus explained. An enclosed sea would destroy some species 

 and admit of the introduction of others to meet the changed 

 conditions. A temporary destruction of some part of the 

 barrier might admit marine types which in the lapse of time 

 majr have changed to new types. 



In summary it may be said that the object of this paper is 

 to show that the Permian of Texas is, like other areas of 

 Permian, such as those in Europe, a deposit in large measure 

 made in an inland sea, at certain times in its history a dead 

 sea. This condition was foreshadowed in later Carboniferous 

 times not only in the lithologic nature of the strata and in the 

 fauna, but also in the topographic conditions, the later Car- 

 boniferous being in all probability deposited in a Mediterranean 

 sea more or less completely landlocked. The Permian was the 

 immediate successor of the Carboniferous, being separated, if 

 at all, by a very slight break, the marked difference in the 

 nature of the beds and the character of the fauna being due 

 rather to changed conditions than to actual time break. 



